Surgical and dental instrument



G. F. RICHTER.

SURGICAL AND DENTAL INSTRUMENT.

APPLICATION FILED MAY 25. I921.

1 437 995 Patented Dec. 5, 1922.

INVENTOE A TORNEYS undesirable Patented Dec. 5, 192 2.

' GUSTAV r. RICHTER, or BROOKLYN, NEW YORK.

SIFBGICAL AND DENTAL INSTRUMENT.

Application filed may 25,

To all whom it may concern:

Be it known that I, GUsrrAv F. RICHTER, a citizen of the United States-,'residing in the borough of Brooklyn, city and State of New York, have invented the following described lmprovements in Surgical and Dental Instruments.

My invention relates to surgical and den tal instruments having a tong-action like hinged retractors, dilators and the like, and more especially mouth gags. Such instruments are commonly provided with latches for retaining them in operating position, expanded or contracted as the case may be, but so far as I am aware all such latches of general application are encumbered by certain features inherent in them. Some are cumberous and more or less interfere with the work of the surgeon or dentist and some are adapted to lock only in one position and hence are not suited for every condition encountered; others are adjustable, that is to say are adapted to hold the tongs expanded (or contracted) in different de grees, but act only by definite and relatively large steps like a pawl and rack bar which is a common form of latch in this art, so that the operator is not always able to stop the instrument in exactly the position he wishes it and the instrument must be expanded (or contracted) still farther to release it. The object of my invention is to provide such instruments with a latch that is at once convenient and out of the way and unencumbered with such characteristics. 7

I The accompanying drawings show the invention embodied in the form of a mouth gag to which it is especially applicable, Fig. 1 being a perspective of the same, Fig. 2 an end view of the gag partly in section, and Fig. 3 a modified form of the device of the preceding figures.

The curved mouth members 1 and 2 of the gag are pivotally united at 3 and 4 adj acent their ends; beyond the pivot lintegral extensions 5 and 6 of the mouth members terminate in handles or grips 7 and 8 bent outwardly in right angles thereto for ex- Banding the gag. It will be understood that. iii use the extensions at 12 on the mouth members are inserted between the patients jaws so as to rest on the teeth; by compressing the handle levers 7 and 8 the gag is expanded and the patients mouth forced open. To hold the gag expanded I provide a latch comprising a cam M on one of the 1921. Serial No. 472,366.

instrument members, to cramp or bind against a co-acting arcuate member 15 mounted on the other instrument member.

The depth or radius of curvature of the cam as shown, which is hinged on the pintle 13, increases gradually from A to B so that the arcuate member slides easily over the cam as the instrument handles are pressed together but is automatically seized as the mouth members 1 and 2 tend to close. The cam therefore automatically locks the arouate member against reverse movement and the instrument in operating position. The handle 16 is arranged for manually releas- 7o ing the arcuate member against the pressure of a flat spring 17 fastened on the inside of one of the handles and normally urging the cam in the locking direction. Either or both the arcuate member and the cam are knurled or provided with serrations at 18 to assure positive engagement between them and the movement of the cam to looking position.- Preferably the cam 14 is disposed in a central slot in the handle extension 6, into both walls of which the pintle 13 extends, and the arc member 15 is made a rigid part of the opposite handle extension and is curved on the pivot 4.- as a center soas to slide in the opposite end of the cam slot, and preferably in engagement with the adjacent end wall thereof. I prefer to make are member 15 as a separate piece andsecure the same to its instrument member; not only does this simplify the fabricationof the instrument to.

but also I am enabled to stamp out the part 15 from mild steel and secure the necessary "hardness in it by case-hardening a few hours. Should this attachment loose its rigidity at any time its engagement with the end wall 85 of the slot permits the cam 14: to clamp it against this end wall as a fixed abutment and thus continue the locking engagement substantially without change. As shown in Fig. 3, the arcuate member 15. maybe hinged to its instrument handle initially in which case the cam clamps it against the slot endwall from the beginning. With either con- 'struction, it will be. observed, the arrangement of the cam 14 and are member 15 in to get out of order or deteriorate with use no.

and furthermore an arrangement wherein all the latch parts are located out of the Way from the slot, brings the locking cam into' of the operator and in such positions as not to interfere with the application of the instrument to the patient.

lit will be apparent that the gag may be readily expanded, the arcuate member riding easily over the cam as the mouth members are opened by compressing the handles; as soon as the handles are released, however, the pressure of the patients jaws on the mouth members tending to close the latter and withdraw the arcuate member locking action and holds the gag expanded in practically the exact position to which it is brought by the operator, there being practically no recession. In order that the gag may be easily opened and closed for cleaning, etc., the rear extension 19 of the cam 14 on which the spring 17 bears, may be so arranged that when the cam has been withdrawn from the arc member 15 to some extent beyond its releasing position, the spring-tends to depress the extension on the opposite side of the hinge pin 13 as shown in Fig. 3, thus farther withdrawing the cam. The projecting pin 20 on the cam limits this movement by striking the handle extension. By withdrawingthe cam 14 as far as possible, in this construction, it may be left temporarily in an open or releasing position and from this position may be restored to automatic action by a manual movement toward the arc 15. v

lit will be apparent that my invention embodies none of the disadvantages that I have mentioned hereinbefore and that while I have shown and described it as embodied in a mouth gag to which it is particularly applicable, it is also applicable to other surgical and dental instruments as appears from the following claims.

Claims:

1. Theconibination with relatively piv oted members of a surgical or dental instrument, of a latch therefor comprising a cam mounted on one of the instrument members and a co-operating member projecting from another of the pivoted members, the cam binding against the projecting member to lock the instrument members against reverse movement.

2. In an instrument of the kind described,

the combination of the tong-like members,

one of which is provided witha slot, a cam mounted in said slot and a co-operating latch member projecting from the other 01 said tong-like members and sliding in the s'lot,-whereby the cam binds the co-operating latch member to lock the instrument in operating position. f

3. In an instrument of the kind described, the combination with the tong-like members and the handlesfor the same, one of the handles being provided With a slot, of an eccentric cam pivoted in one end of said slot, a co-operating latch member projecting fromthe other handle and sliding in the other end of the slot, whereby said cam binds against the co-operating member to lock the instrument in operating position, and spring means normally holding the cam against the co-operating member.

4. In an instrument of the kind described, the combination with the tong-like members thereof, one. of which is provided with a locking wall, of an eccentric cam pivoted to the member having thewall, and a cooperating latch member attached to the other of said instrument members and sliding between said cam and Wall, whereby said co-operating member may be cramped against said wall to lock the instrument in operating position.

5. In an instrument of the kind described, the combination with the tong-like members thereof, of an eccentric cam pivotedto one of the instrument members, a, co-operating latch member projecting from the other of said instrument members whereby said cam binds against the co-operating member to lock the instrument in operating position, and spring means normally holding the cam against the co-operating member and also adapted to hold the cam retracted.

6. In a surgical instrument, the combination of pivoted tong-like members, and a latch comprising a cam mounted on one of saidmembers, and a co-operating arcuate member projecting from the other of said tong-like members, the cam binding against said arcuate member to lock the instrument In testimony whereof, l[ have signed this specification.

GUSTAV lF. RICHTER, 

